Powering the quantum revolution: Quantum engines on the horizon

Phys.org  September 27, 2023 Quantum theory offers genuine non-classical forms of energy, different from heat, which so far have not been exploited in cyclic engines. An international team of researchers (Germany. Japan, Argentina) experimentally realized a quantum many-body engine fueled by the energy difference between fermionic and bosonic ensembles of ultracold particles that follows from the Pauli exclusion principle. They employed a harmonically trapped superfluid gas of 6Li atoms close to a magnetic Feshbach resonance that allowed them to effectively change the quantum statistics from Bose–Einstein to Fermi–Dirac, by tuning the gas between a Bose–Einstein condensate of bosonic molecules and […]

Optical memristors review: Shining a light on neuromorphic computing

Phys.org  June 5, 2023 In recent years, the ability to vary the conductance of a channel in electronics has enabled in-memory computing, thus leading to substantial interest in memristors. An international team of researchers (USA – University of Pittsburg, University of Maryland, Germany, UK) reviewed recent progress in this important and emerging aspect of photonic integrated circuits and provided an overview of the current state of the art. They shed light on the evolution of this technology—and the work that still needs to be done for it to reach its full potential. They have provided a comprehensive overview of recent […]

Wafer-scale nanofabrication of telecom single-photon emitters in silicon

Phys.org  February 23, 2023 Monolithic integration of single-photon sources in a controllable way would give a resource-efficient route to implement millions of photonic qubits in photon integrated circuits. To run quantum computation protocols, these photons must be indistinguishable. Building on their previous work researchers in Germany have shown how focused ion beams from liquid metal alloy ion sources are used to place single-photon emitters at desired positions on the wafer while obtaining a high creation yield and high spectral quality. After several cooling-down and warming-up cycles, there was no degradation of their optical properties. To allow for wafer-scale engineering of […]

New method can improve explosion detection

Science Daily  July 22, 2022 Explosions produce infrasound waves capable of propagating globally, but the spatio-temporal variability of the atmosphere makes detecting events difficult. Machine learning (ML) is well-suited to identify the subtle and nonlinear patterns in explosion infrasound signals, but a previous lack of ground-truth data inhibited training of generalized models. A team of researchers in the US (University of Alaska, Air Force, University of Mississippi, Los Alamos National Laboratory) has developed a physics-based method that propagates infrasound sources through realistic atmospheres to create 28,000 synthetic events, which are used to train ML classifiers. A simple artificial neural network […]

Magnetic spins that ‘freeze’ when heated: Nature in the wrong direction

Nanowerk  July 4, 2022 An international team of researchers (the Netherlands, Sweden) observed an unusual magnetic transition in elemental neodymium where, with increasing temperature, long-range multiply periodic ‘multi-Q’ magnetic order emerged from a self-induced spin glass. They characterized the local order of a previously reported spin glass phase and quantified the emergence of long-range multi-Q order with increasing temperature. Using the analysis tools they developed, they determined the glass transition temperature from measurements of the spatially dependent magnetization. They compared these observations with atomistic spin dynamics simulations to reproduce the qualitative observation of a phase transition from a low-temperature spin […]

Researchers develop silicon cuboid nanoantenna

Phys.org  March 21, 2022 The Purcell effect is commonly used to increase the spontaneous emission rate by modifying the local environment of a light emitter. Researchers in China studied the scattering cross section, polarization charge distribution, and electromagnetic field distribution for electromagnetic plane wave illuminating the silicon dielectric cuboid nanoantenna and identified simultaneous existence of electric dipole (ED), magnetic dipole (MD) and electric quadrupole (EQ) emission resonance modes in this nanoantenna. When they calculated the Purcell factor of ED, MD, and EQ emitters with different moment orientations as a function of radiation wavelength by placing these point radiation source within […]

This 500-Year-Old Landslide Found in The Red Sea Could Trigger a Future Tsunami

Science Alert  February 28, 2022 Tsunamigenic submarine landslides are common in deep, steep-sided, and seismically active basins of the Red Sea. Because the rift is narrow, tsunami formed on one margin dissipate little before impacting the opposite side. An international team of researchers (USA – University of Miami, UC Santa Cruz, industry, Columbia University, Italy, Saudi Arabia) examined the tsunamigenic potential of an incipient landslide in the Tiran Straits that started, but then stopped after a short distance. Their analyses fix the age of this landslide to within the last 500 years. Tsunami modeling predicts ∼10 m wave heights on […]

A-list candidate for fault-free quantum computing delivers surprise

Science Daily  December 22, 2021 Spin-triplet pairing is important because it can host topological states and majorana fermions relevant for quantum computation. Because spin-triplet pairing is usually mediated by ferromagnetic (FM) spin fluctuations, uranium-based materials near an FM instability are ideal candidates for realizing spin-triplet superconductivity. UTe2 has been identified as a candidate for a chiral spin-triplet topological superconductor near an FM instability, although it also has antiferromagnetic (AF) spin fluctuations. A team of researchers in the US (Rice University, Florida State University, Oak Ridge National Laboratory, UC San Diego, Arizona State University) used inelastic neutron scattering (INS) to show […]

Soft semiconductors that stretch like human skin can detect ultra-low light levels

Science Daily  December 15, 2021 An international team of researchers (USA – Georgia Institute of Technology, Chile) has demonstrated a new level of stretchability for a photodetector made from a synthetic polymer and an elastomer that absorbs light to produce an electrical current. It is up to 200% more stretchable than its original dimension without significantly losing its electric current. They found the right combination of chemical compounds to produce a super-soft material with the ability to generate and conduct electricity when exposed to light and the right ratio for all parts of the semiconductor layer to maintain high performance […]

Molecular interfaces for innovative sensors and data storage devices

Nanowerk October 20, 2021 To better understand electronic and magnetic properties and understanding the mechanisms that govern the interactions at the interface an international team of researchers (Germany, Austria, Switzerland, Italy) coupled nickel-porphyrin with copper. Using theoretical and experimental spectro-microscopy approach they showed that the charge transfer occurring at the interface between nickel tetraphenyl porphyrins and copper changes both spin and oxidation states of the Ni ion. The chemically active Ni(I), even in a buried multilayer system, can be functionalized with nitrogen dioxide, allowing a selective tuning of the electronic properties of the Ni center that is switched to a […]